now our life is better and better ,but the only earth gets dirtier and dirtier .so i think we should do something to make our world clean.what we should do we must stop people from throwing litter everywhere and river.Becuase litter can pollut our world .we should let people take buses instead of taking their cars.and taking cars is bad for air .i think we can do more things to make our world clean.let we do them togther